I have been looking into getting a 6x6 version of one of these as my next vehicle in the next couple months. I was talking to my brother about it since he's a diesel mechanic. He is slightly biased but said I should consider doing a cummins 6.7 swap as it's a similar size but just a bit taller. He has a bunch of training from Cummins and experience with the engines and said it's not an issue to get rid of any emissions stuff. Has anyone ever done this? I would definitely be interested and he could get me one fairly cheap if it would be possible .